Method and system for controlling pressurization of a patient cavity using a pressure sensor in a trocar

ABSTRACT

According to one embodiment, a method includes positioning a trocar having a primary pressure sensor in or on the trocar into a patient cavity. The method also includes supplying an insufflation fluid to the patient cavity and measuring a pressure in the patient cavity by the primary pressure sensor. The method further includes controlling the supply of insufflation fluid by an insufflator to the patient cavity based at least on the measured pressure and determining by a processor associated with the insufflator that the measured pressure may be inaccurate and in response, controlling, by the insufflator, the supply of insufflation fluid to the patient cavity based at least on a pressure measured by a backup pressure sensor rather than based on the measured pressure.

TECHNICAL FIELD OF THE INVENTION

The present invention disclosure relates generally to medical proceduresand more particularly to a method and system for controllingpressurization of a patient cavity using a pressure sensor in a trocar.

BACKGROUND OF THE INVENTION

Laparoscopic surgery is a standard procedure in hospitals. Abdominal andchest cavity operations are being performed with instruments insertedthrough small incisions into interior portions of the body. Suchlaparoscopic procedures are now considered the treatment of choice foroperations such as the removal of the gall bladder, spleen, adrenalglands, uterus, and ovaries. These laparoscopic procedures areaccomplished via access through a device typically known as a trocar. Atrocar facilitates the introduction of laparoscopic instruments into theabdomen or chest of the body. These instruments are typically introducedinto regions under fluid pressure. This fluid may be a gas, referred toherein as an insufflation gas.

Providing an insufflation gas into a body cavity is referred to asinsufflation. Currently, insufflation is performed by providing aregulated pressurized insufflation gas to the peritoneal cavity via acannula of the trocar. This insufflation gas, typically carbon dioxide,is supplied to a connection on the trocar tube by a flexible hoseattached thereto. The medical instrument going through the innermosttube of the trocar should be sealed relative to the trocar so theinsufflation gas will not escape from the patient.

A physician can use a trocar device to introduce different types ofinstruments into a patient. In order to reduce incisions into the body,typically the insufflation gas is delivered into a body cavity duringspecific medical procedures or treatment is done via a trocar that alsoallows insertion of an instrument via the innermost tube of the trocar.The purpose of using such a device is to inflate or distend the bodycavity to (1) allow the surgeon to explore the area in which the surgerywill be performed and (2) provide a view of the site to be treated orobserved.

Insufflation is used in many common procedures including endoscopicsurgical procedures, laparoscopic procedures performed on the abdominalcavity and orthoscopic procedures performed on the chest cavity.Additional trocars can be used during the same surgical procedure toremove surgical smoke from the patient cavity or to continuously measurepressure within the body cavity. These trocars typically also allow forthe insertion of an instrument via the innermost tube of the trocar.

SUMMARY OF THE INVENTION

According to one embodiment, a method includes positioning a trocarhaving a primary pressure sensor in or on the trocar into a patientcavity. The method also includes supplying an insufflation fluid to thepatient cavity and measuring a pressure in the patient cavity by theprimary pressure sensor. The method further includes controlling thesupply of insufflation fluid by an insufflator to the patient cavitybased at least on the measured pressure and determining by a processorassociated with the insufflator that the measured pressure may beinaccurate and in response, controlling, by the insufflator, the supplyof insufflation fluid to the patient cavity based at least on a pressuremeasured by a backup pressure sensor rather than based on the measuredpressure.

The teachings of the disclosure provide one or more technicaladvantages. Embodiments of the disclosure may have none, some, or all ofthese advantages. For example, in some embodiments, a method allows forcontinuous monitoring of pressure associated with a patient cavity evenin the event of a pressure sensor failure. This allows safe completionof a surgical procedure without subjecting the patient to potential harmassociated with deactivation of an associated insufflator. Further,providing a pressure sensor in conjunction with the trocar nearer thepatient cavity provides better pressure sensing and more stable controland does not require stopping the associated surgical procedure tomeasure pressure according to certain standard techniques.

Other advantages will be apparent to those of skill in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of embodiments of the disclosure andthe potential advantages thereof, reference is now made to the followingwritten description taken in conjunction with the accompanying drawings,in which:

FIG. 1 is a schematic diagram showing the distal end of a trocar havingan associated pressure sensor, the distal end placed in the abdominalcavity of a patient;

FIGS. 2A and 2B are block diagrams illustrating additional details ofcomponents of the system of FIG. 1 that may be used to effect pressuredetermination and resulting actions; and

FIG. 3 is a flow chart illustrating a method that includes switchingcontrol of an insufflator to be based on pressure measurements of abackup pressure sensor.

DETAILED DESCRIPTION OF THE INVENTION

The present disclosure relates to a method for controllingpressurization of a patient cavity. The teachings of the disclosurerecognize that more accurate control of such pressurization can occur bymeasuring the pressure in a patient cavity directly through use of apressure sensor located on or associated with a trocar such that thepressure sensor is in direct contact with the gas region in the patientcavity but that in some instances such pressure sensors can be damagedand provide erroneous data. As such, it can be desirable to monitor suchpressure measurements, and when the data appear faulty, switch controlof such pressurization to be based on a secondary or back up measure ofpressure within the pressure cavity. In some embodiments, a backuppressure sensor located in or on the insufflator is used to provide sucha backup pressure measurement, and in some embodiments a backup pressuresensor is located in or on the trocar.

Example embodiments are best understood by referring to FIGS. 1 through3B of the drawings and the description below, like numerals being usedfor like and corresponding parts of the various drawings.

FIG. 1 is a schematic diagram showing the distal end 24 of a trocar 14placed in the abdominal cavity 20 of a patient. In general, aninsufflator 10 supplies insufflation gas through conduit 12 and trocar14 to patient cavity 20. Trocar 14 allows insertion of a surgicalinstrument 28 into patient cavity 20.

Trocar 14 has a primary pressure sensor 22 on or associated with thetrocar 14. The location can be anywhere in or on trocar 14 or associatedwith trocar 14; however, as described in greater detail below, in oneembodiment primary pressure sensor 22 is located on the exterior oftrocar 14 such that changes of pressure within trocar 14 due to supplyof insufflation gas to patient cavity 20 do not affect the pressuremeasured by primary pressure sensor 22. In some embodiments, primarypressure sensor 22 is an absolute pressure sensor that can measurepressure in patient cavity 20 (if disposed within patient cavity 20) orin the room in which the associated operation is taking place.

Primary pressure sensor 22 is coupled to insufflator through anysuitable technique, including a wired connection 25 or a wirelessconnection. Primary pressure sensor 22 supplies pressure data toinsufflator 10. Insufflator 10 uses this pressure data to control thesupply on insufflation gas by insufflator 10. In particular embodiments,this may include determining the change in height of trocar 14 relativeto changes in cavity pressure and thus the resulting change in height ofpatient cavity 20, as described in greater detail in co-pendingapplication Ser. No. 15/293,013 entitled Method and System forControlling Pressurization of a Patient Cavity Using Cavity DistensionMeasured by a Pressure Sensor of a Trocar incorporated herein byreference. Additional details of certain portions of FIG. 1 aredescribed below.

Insufflator 10 may be any suitable source of insufflation gas at anysuitable pressure and may include a pressurized gas source. Insufflatormay adjust the supply of insufflation gas to patient cavity 20 byadjusting the pressure and/or the volume of insufflation gas supplied topatient cavity 20. Insufflator may include appropriate hardware and/orsoftware for processing signals indicative of pressures measured byprimary pressure sensor 22 and processing such signals to convert theminto useful information, such as converting them into pressures,heights, and/or other data that can be used control the flow ofinsufflation gas to patient cavity 20, and further for processing suchdata to determine a desired pressure and/or volume of insufflation gassupplied to patient cavity 20 and for effecting such delivery.

Conduit 12 may be any suitable conduit for providing an insufflation gasto a portion of a trocar. An example of conduit 12 includes flexible PVCtubing. The insufflation gas may be any suitable gas used forinsufflation purposes. In one example, insufflation case is carbondioxide.

Trocar 14 may be any suitable trocar through which insufflation gas maybe supplied to a patient cavity. Examples of one or more trocars areprovided in U.S. Pat. No. 8,715,219 (the '219 patent), U.S. Pat. No.7,285,112 (the '112 patent), and U.S. Pat. No. 8,216,189 (the '189patent), which are hereby incorporated by reference as if fully setforth herein. Trocar 14 may be have a single lumen or may be formed withan inner tubular lumen and an outer tubular lumen such that insufflationgas may be supplied through one of the lumens but not the other.Further, any of the lumens may be divided into multiple, separatechambers, such that gas in one chamber does not enter the other chamber.Examples of the above multiple lumens and multiple chambered trocars aredescribed in U.S. application Ser. No. 14/792,873, entitled “Method andSystem for Gas Maintenance to a Body Cavity Using a Trocar,” which ishereby incorporated by reference. Trocar 14 may be open or closed at thedistal end 24, as the application of the trocar would allow.

Primary pressure sensor 22 may be any sensor capable of sensing pressureor a change in pressure. Primary pressure sensor 22 may measure absolutepressure or a pressure relative to some other pressure. In someembodiments, primary pressure sensor 22 is an absolute sensor that canmeasure pressure in patient cavity 20 (if disposed within patient cavity20) or in the room in which the associated operation is taking place. Inparticular embodiments, primary pressure sensor 22 can measure absolutebarometric pressures with an accuracy of less than 1 Pascal pressure andtherefore have the ability to measure the relative changes in altitudeof close to one inch. Such pressure sensors are readily available in themarketplace.

FIGS. 2A and 2B are block diagrams illustrating additional details ofcomponents of the system of FIGURE that may be used to effect pressuremeasurement and resulting insufflator control. FIG. 2A illustratesadditional details of insufflator 10, according to one embodiment. Inthis embodiment, insufflator 10 includes a memory 40 and a processor 42communicatively coupled to the memory 40. Memory 40 stores a pressureapplication 44, which may include logic for effecting pressure andaltitude determination as described with respect to the other FIGURES aswell as control of the supply of insufflation gas to patient cavity 20.According to the teaching of the disclosure, a backup pressure sensor 26is provided. In one embodiment, insufflator 10 includes a backuppressure sensor 26. Backup pressure sensor 26 may be used to measurepressure associated with trocar 14 in the event or problems associatedwith primary pressure sensor 22, as described in greater detail below inconjunction with FIG. 3. In another embodiment, backup pressure sensor26 is provided on trocar 14, as illustrated in FIG. 1. The teachings ofthe disclosure recognize that primary pressure sensor 22 may experienceproblems due to being located a larger distance from an associatedprocessor, which leads to potential for erroneous readings andinterference. In addition exposing primary pressure sensor 22 tocontamination, such as from blood and to humidity also contribute topotential problems being experienced by primary pressures sensor 22.Backup pressure sensor 26 may be any suitable pressure sensor, includingthe pressure sensors described above as being suitable as primarypressure sensor 22.

FIG. 2B illustrates an alternative embodiment of the system of FIG. 1 inwhich an insufflator 110 includes only standard features and iscommunicatively coupled through a connection 114 to a pressure module112. Pressure module 112 includes components analogous to thosedescribed with respect to FIG. 2A, including a backup pressure sensor126, but are included in this stand-alone pressure module. Connection114 between insufflator 110 and pressure module 112 may be wired orwireless. It will be understood that although a software-based system isillustrated in FIGS. 2A and 2B the logic described herein could insteadbe implemented through hardware circuits or a combination of hardwareand software.

FIG. 3 is a flow chart illustrating a method 200 that includes use of aprimary pressure sensor and a backup pressure sensor associated with atrocar. The method may utilize structural items such as those describedin FIGS. 1A through 2B or may use alternative structural items.Computational steps described below may be performed by any suitablecomputation device, including insufflator 10 and pressure module 112,for example.

The method begins at step 202.

At step 204, at least a portion of a trocar having a primary pressuresensor is positioned in a patient cavity. The pressure sensor in locatedon, or associated with, the trocar such that the primary pressure sensorcan provide a direct measurement of a pressure in a patient cavity whena portion of the trocar is positioned in the patient cavity. At step206, the primary pressure sensor repeatedly measures a pressure withinthe patient cavity and communicates a signal indicative of themeasurement to a processor associated with an insufflator. Also at step206, the processor analyzes the measured pressure for indications ofwhether the signals indicative of the measured pressure being inaccurateor otherwise suggesting that the primary pressure sensor is operating ina less than optimal manner. Any suitable factors may be considered insuch analysis; however, certain factors that may indicate the primarypressure sensor is operating than a less than optimal manner include (1)whether the received signal is not within an expected range for thereceived signal; (2) whether error data is received, such as whethererrors have occurred due to interference from a power signal, the wrongnumber of bits have been received, data is received in the wrong format,or data is received with improper spacing (3) whether properacknowledgment bits are not received from the primary pressure sensor,(4) whether the received signal is not within an expected voltage range,(5) whether expected new updated status bits are not received, such aswhether a signal has changed enough to indicate a new measurement hasoccurred as opposed to a signal being so close to a previous signal toindicate no new measurement has occurred; and (6) in the case of two ormore pressure sensors located on or near trocar 14, whether measurementsby the two or more sensors are not within a certain range of each other.

At step 208, a processor determines, whether the above analysis suggeststhe primary pressure sensor is not measuring accurately or otherwise notoperating in a less than optimal fashion. If not, then processingreturns to step 206, and if so, the control by the insufflator isswitched to be based on pressure sensed by a backup sensor at step 210.

Although the pressure sensed by a backup pressure sensor 210 is usuallynot as accurate a measure of the pressure within the patient cavity andas such not as desirable for use in controlling an insufflatorassociated with a trocar, when problems arise with a primary pressuresensor positioned on or associated with a trocar such the directpressure measurements within a patient cavity can be made, it can beadvantageous to at least temporarily switch control to be based onpressure measurements made by a backup pressure sensor located at theinsufflator.

The method concludes at step 212.

Thus, a method and system have been described that uses backup pressuresensor for pressure measurements associated with an insufflator when itis determined that pressure measurements associated with a primarypressure sensor may be inaccurate. By doing so, advantages associatedwith locating a pressure sensor nearer the patient cavity may berealized.

Although one embodiment has been illustrated and described in detail, itwill be understood that various substitutions and alterations can bemade therein without departing from the spirit and scope of the presentinvention, as defined by the following claims.

What is claimed is:
 1. A system for supplying insufflation fluidcomprising: a trocar; a first primary pressure sensor positioned on orin the trocar and a second primary pressure sensor positioned on or inthe trocar; a backup pressure sensor not positioned on or in the trocar;and an insufflator communicatively coupled to the primary pressuresensor, the insufflator further comprising: a processor acomputer-readable media having logic stored thereon, the logic operable,when executed on the processor, to: receive pressure measurements fromthe first primary pressure sensor and the second primary pressure sensorwhen the trocar is positioned in a patient cavity; control the supply ofinsufflation fluid from the insufflator to the patient cavity based atleast on the pressure measurements from the first primary pressuresensor on or in the trocar; compare the pressure measurements from thefirst primary pressure sensor on or in the trocar to the pressuremeasurements from the second primary pressure sensor on or in thetrocar; and determine that the pressure measurements from the firstprimary pressure sensor on or in the trocar may be inaccurate based onthe comparison, and in response, control supply of insufflation fluid bythe insufflator to the patient cavity based at least on a pressuremeasured by the backup pressure sensor rather than based on the pressuremeasurements from the first primary pressure sensor on or in the trocar.2. The system of claim 1, wherein the first primary pressure sensor ispositioned on the exterior of the trocar.
 3. The system of claim 1,wherein the insufflation fluid is a gas that is supplied to the patientcavity through the trocar.
 4. The system of claim 1, wherein the backuppressure sensor is located within the insufflator.
 5. A methodcomprising: positioning a trocar having a first primary pressure sensorin or on the trocar and a second primary pressure sensor in or on thetrocar into a patient cavity; supplying an insufflation fluid to thepatient cavity; measuring a pressure in the patient cavity by the firstprimary pressure sensor and by the second primary pressure sensor;controlling the supply of insufflation fluid by an insufflator to thepatient cavity based at least on the pressure measured by the firstprimary pressure sensor; comparing the pressure measurements from thefirst primary pressure sensor in or on the trocar to pressuremeasurements from the second primary pressure sensor in or on thetrocar; and determining by a processor associated with the insufflatorbased on the comparison, that the pressure measured by the first primarypressure sensor in or on the trocar may be inaccurate and in response,controlling, by the insufflator, the supply of insufflation fluid to thepatient cavity based at least on a pressure measured by a backuppressure sensor not located in or on the trocar rather than based on thepressure measured by the first primary pressure sensor in or on thetrocar.
 6. The method of claim 5, wherein the first primary pressuresensor is positioned on the exterior of the trocar.
 7. The method ofclaim 5, wherein the insufflation gas is supplied to the patient cavitythrough the trocar.
 8. A method comprising: positioning a trocar havinga first primary pressure sensor in or on the trocar and a second primarypressure sensor in or on the trocar into a patient cavity; supplying aninsufflation fluid to the patient cavity; measuring a pressure in thepatient cavity by the first primary pressure sensor in or on the trocar;controlling the supply of insufflation fluid by an insufflator to thepatient cavity based at least on the pressure measured by the firstprimary pressure sensor in or on the trocar; comparing the pressuremeasurements from the first primary pressure sensor in or on the trocarto pressure measurements from the second primary pressure sensor in oron the trocar; determining by a processor associated with theinsufflator based on the comparison that the pressure measured by thefirst primary pressure sensor in or on the trocar may be inaccurate andin response, controlling, by the insufflator, the supply of insufflationfluid to the patient cavity based at least on a pressure measured by abackup pressure sensor rather than based on the pressure measured by thefirst primary pressure sensor in or on the trocar; and wherein thebackup pressure sensor is located within the insufflator.
 9. Aninsufflator comprising: a pressurized fluid source; a processor; and acomputer-readable media having logic stored thereon, the logic operable,when executed on the processor, to: receive pressure measurements from afirst primary pressure sensor positioned on or in a trocar and a secondprimary pressure sensor positioned on or in a trocar, the trocarpositioned in a patient cavity; control the supply of insufflation fluidfrom the pressurized fluid source to the patient cavity based at leaston the pressure measurements from the first primary pressure sensor onor in the trocar; comparing the pressure measurements from the firstprimary pressure sensor on or in the trocar to pressure measurementsfrom the second primary pressure sensor on or in the trocar; anddetermine based on the comparison, that the first pressure measurementsfrom the first primary pressure sensor may be inaccurate and inresponse, control the supply of insufflation fluid by the pressurizedfluid source to the patient cavity based at least on a pressure measuredby a backup pressure sensor not located on or in the trocar rather thanbased on the pressure measurements from the first primary pressuresensor on or in the trocar.
 10. The insufflator of claim 9, wherein theprimary pressure sensor is positioned on the exterior of the trocar. 11.The insufflator of claim 9, wherein the backup pressure sensor islocated within the insufflator.
 12. A computer-readable media havinglogic stored thereon, the logic operable, when executed on a processor,to: receive pressure measurements from a primary pressure sensorpositioned on or in a trocar and a second primary pressure sensorpositioned on or in the trocar, the trocar positioned in a patientcavity; control the supply of insufflation fluid, by an insufflator, tothe patient cavity based at least on the pressure measurements from thefirst primary pressure sensor on or in the trocar; comparing thepressure measurements from the first primary pressure sensor on or inthe trocar to pressure measurements from the second primary pressuresensor on or in the trocar; and determine, based on the comparison, thatthe pressure measurements from the primary pressure sensor may beinaccurate and in response, control the supply of insufflation fluid bythe insufflator to the patient cavity based at least on a pressuremeasured by a backup pressure sensor rather than based on the pressuremeasurements from the first primary pressure sensor on or in the trocar.13. The computer-readable media of claim 12 wherein the backup pressuresensor is located within the insufflator.